Code & Data
Convert YAML to JSON
Paste YAML and get JSON. It handles what configuration files actually contain — and refuses what it cannot read correctly, rather than quietly producing something that is nearly right.
Indentation
What this does not support
- • Anchors and aliases (&name and *name)
- • Merge keys (<<)
- • Explicit tags (!!str, !Custom)
- • Multiple documents in one file (---)
- • Complex mapping keys (? and :)
Anything on this list is reported as an error rather than guessed at. Everything a normal configuration file contains — block maps and lists, quoted and plain scalars, inline collections, comments, and literal or folded blocks — is handled.
Paste YAML above and the JSON appears here.
- Runs in your browser
- No account required
- Free to use
How it works
The boundary is the feature
Full YAML 1.2 is a large specification: anchors and aliases, merge keys, tags, multiple documents, several kinds of block scalar with two chomping indicators each, and typing rules that changed between versions. Implementing most of it is how you get a parser that reads a config file slightly wrong and reports success. This one handles block maps and sequences, quoted and plain scalars, inline collections, comments, and literal and folded blocks — and reports anything else as an error, with the list of what it does not support on the page.
Typing follows the quotes
Unquoted `yes`, `no`, `true`, `null` and `~` are typed as YAML says; quoted, they stay strings. That is the Norway problem — the country code NO read as a boolean — and getting it right is the difference between a config that loads and one that does not.
A long ID stays a string
An integer beyond the range JavaScript can represent exactly is kept as a string rather than silently becoming a different number. An ID that changes value in conversion is a worse outcome than one that stays text.
What it does
Comments handled properly
A `#` only starts a comment after whitespace, so `http://x/y#z` and `pass#word` stay intact — a mistake that catches a surprising number of converters.
Literal and folded blocks
Both `|` and `>` are supported, with the strip and keep chomping indicators, so a multi-line script or description converts correctly.
Errors name the line
An unsupported construct or a malformed line is reported with its line number and what to do about it.
Nothing is uploaded
Config files routinely hold secrets. This one is parsed in your browser and the page makes no network requests at all.
Practical advice
Getting a better result
- If it refuses anchors, expand them first — most editors can do this, and the expanded file is usually clearer anyway.
- YAML is whitespace-significant and tabs are not valid indentation. If a file will not parse, check for a tab that got in.
- Quote anything that should stay a string, especially version numbers, country codes and values that look like booleans.
Questions
Things people ask
Which YAML features are not supported?
Anchors and aliases, merge keys, explicit tags, multiple documents in one file, and complex mapping keys. Each is detected and reported rather than mis-parsed. Everything a normal configuration file contains is handled.
Why is my value a boolean when I wanted a string?
Because unquoted `yes`, `no`, `on` and `off` are booleans in YAML. Put quotes around them to keep them as text — this is the well-known "Norway problem", where the country code NO becomes false.
Does it convert JSON back to YAML?
That direction is a separate tool, and it is easier: writing YAML means picking one output form, while reading it means accepting every form the specification allows.
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Open toolWho builds these
Free tools by day. Websites that earn their keep by trade.
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This tool runs entirely in your browser. Your files are never uploaded.